INSTINCTS AND HABITS IN CHICKS 15 



The food dish was kept out of the chicks' field of view and 

 the bits of food to be pecked at were dropped by hand upon the 

 cardboard in such a way that a particle would not be in motion 

 when a chick peeked at it. From one to three grains only were 

 dropped at a time. This proved advisable because the number 

 of reactions elicited by more than three grains, considering also 

 the possible variety and rapidity of the reactions, made it 

 difficult at times to secure an accurate record. 



In a letter published by Mills,' Bumpus ^ has suggested that 

 the different aspects of the pecking reaction be distinguished. 

 For these separate parts he proposed the terms seizure, mouth- 

 ing or mulling, and deglutition. The terms used by Morgan ' 

 seem much more appropriate — striking, seizing, and swallow- 

 ing. It is interesting to, note that Spalding " distinguished these 

 phases of the reaction and employed the same terms. These 

 we have adopted, using in addition the term missing for failure 

 to hit the object. As they appear in our records, these terms 

 have the foUovring definite meanings: (i) Missing denotes all 

 cases of the pecking reaction in which the bill fails to hit the 

 particular object supplied, by the experimenter; (2) striking, 

 those cases in which the bill hits the object without seizing it; 

 (3) seizing, cases in which the object is grasped momentarily 

 in the bill and then dropped; and (4) swallowing denotes what 

 may be termed the perfect or complete reaction, the object being 

 struck, seized, and swallowed in an errorless series or chain of 

 movements. To facilitate the taking of records, the numerals 

 I, 2, 3, and 4 were used to represent missed, struck, seized, and 

 swallowed, respectively. Note was taken, of course, of the reac- 

 tions independently of the number of fopd particles pecked at, 

 for a single grain might call forth a half dozen reactions in suc- 

 cession. For example, suppose one millet seed brought the 

 result 1-2-3-4. In this case the chick first missed the grain, 

 on the second reaction it struck it but did not get hold of it 

 between its mandibles, on the third attempt it caught it in 

 its bill but dropped it, and on the fourth, it struck, seized, and 

 swallowed the grain without error. 



1 Mills, W.: The nature and development of animal intelligence. New York, 

 1898, p. 296. 



''Bumpus, H. C: Instinct and education in birds. Science, N. S., 1896, vol. 

 4, p. 213. 



'Morgan, C. L.: Habit and instinct. London and New York, 1896, p. 37 



* Spalding, D. A.: Loc. cit. 



